Well, I need some technical knowledge. I bought a Denny's DS and had it installed at the same time as a 3.73 gear. The shop could not get the DS to stop vibrating. It would vibrate at 85 mph. So they re-installed the stock shaft and they were saying the shaft was not balanced. Turns out the stock shaft now vibrates at ( you guessed it ) 85mph.Oh yeah, they installed thenew shaft with an impact. So Iinstalled the new shaft today with a torque wrench and ( you guessed it ), it vibrated at 85 mph.

Enough background!

I put a dial indicater on the differential where the adapter plate mounts before I mounted the shaft. It showed as much as .003 runout as I rotated the wheels.

The question is............. Could the gear be installed incorrect and cause the .003 runout? I know there was no vibration before the work was done.

Thanks for the help.

 

That is a lot of runout. Are you checking it on the stock companion flange or the Denny adapter. Grab the flange & see if you can rock it back & forth or in & out, if you can the pinion bearings aren't properly loaded & the install needs to be checked. I installed my own Spyder Aluminum Driveshaft which uses a replacement flange, I have no vibes. I heard Denny is going this route to stop problems. The install is a little more involved but in your case it would have been easier cause the rear was redone at the same time.

 

Dennys specs say .001 of runout is ok so that means that something is not correct. Make sure the surface is clean before putting the adapter plate on.

 

Have a friend who is going through the same problem with the Denny's driveshaft. Tried all the usual fixes (180 degree turn etc.)

His driveshaft was also installed with an impact wrench instead of with a torque wrench. Current thinking is that the adapter plate was damaged. He's having Denny send him a new one ($75) and he's installing it himself this time.

 

I checked the runout at the companion flange and at the adapter flange. It had .003 runout on the companion flange, and .002 runout on the adapter flange.

I cleaned the area beforeI made the checks.

Thanks for the replies